Breast cancer is the leading form of cancer diagnosed in older women, yet little is known about the physical and social disabilities associated with the disease. The purpose of this project is to assess the functional needs of older women with invasive breast cancer at 3 and 12 months after diagnosis compared to older women in the community without breast cancer. Second, an examination will be made among breast cancer patients of biomedical, demographics, and social factors, assessed 3 months after diagnosis, that are associated with subsequent differences in functioning 9 months later. The independent significance of social support networks for meeting functional needs also will be assessed. A total of 523 older women aged 55 to 80, newly diagnosed with invasive breast cancer in the Detroit Metropolitan area, will be interviewed at 3 and 12 months after diagnosis. A population-based control group of 517 older women without breast cancer also will be interviewed twice over the same period. Biomedical and treatment data for breast cancer cases will be obtained from the population-based Metropolitan Detroit Cancer Surveillance System (MDCSS) operated by the Division of Epidemiology, Michigan Cancer Foundation. Multivariate techniques will be employed to assess differences in physical and social functioning, occupational status and performance, and economic resources. This research is designed to provide an assessment of functional needs, occupational performance, and economic resources, which may suggest, in turn, rehabilitation programs for those older women with breast cancer in greatest need.